Connector



f Filed Nov. 4, `1944 Feb. 2l, 1950 R. R. sTx-:INKE

CONNECTOR 2 Sheets-Sheet 1 ROBE/Q7' R. STEM/KE BY Z/QM M" Mar/rey Feb. 2l, 1950 R. R. sTElNKE 2,498,589

' CONNECTOR Filed Nov. 4, 1944 2 sheetsheet 2 IN V EN TOR.

ROBERT STEM/KE BY Patented Feb. 21, 1950 CONNECTOR Robert R. Steinke, West Somerville, Mass., as-

signor, by mesne assignments, to the United States of America as represented by the Secretary of War Application November 4, 1944, serial No. 561,939

(c1. 11a-32s) 4 Claims. l

The present invention relates to a high voltage cable connector or detachable coupling for use in circuits requiring cables to conduct high voltage pulses. It is more particularly directed toward a connector for use with coaxial type cables, such as are used in high voltage modulator circuits, for example, those where a high voltage cable must be used to connect a pulse-forming network to a rotary spark gap which is usually attached to the shaft of a driving motor. In circuits required to conduct high voltage pulses, it is necessary to provide a connector or coupling unit for the cable which will not fail due to corona or sparkover.

The principal purpose of the present invention is to provide a readily detachable plug connector or coupling which will at the same time be effective to terminate the cable.

Another object of the invention is to provide a connection which will have good electrical conductivity at high voltage and which is not subject to failure due to flash over or corona.

Other features and advantages of the invention will become readily apparent as the description proceeds, reference being had to the accompanying drawings wherein a preferred form of the invention is shown. It is to be understood, however, that the drawing and description are illustrative only and are not to be taken as limiting the invention to the specific details set forth.

In the drawings:

Fig. 1 is a sectional view on a diametrical plane through the plug element of the present invention showing a cable end attached thereto;

Figure 1A is a detail of the parts coupling the plug and socket shown in Figures 1 and 2;

, Fig. 2 is a sectional view on a diam'etrical plane through a preferred embodiment of the socket element of the present invention; andv Fig. 3 is an expanded, perspective view of one form of a, cable end showing the construction thereof and indicating the manner in which several members of the plug element are applied to the cable end.

With reference toFig. 1, the plug element comprises a body portion shaped as a hollow cylinder or cylindrical shell II) of steel, brass, or other suitable metal, the rear end (to the left in Fig. 1) of which is externally threaded at to receive an internally threaded cylindrical clamping nut I2. Clamping nut I2 has an inwardly disposed flange I3 adapted to llt over and abut a flange portion I4 extending outwardly substantially at right angles from the inner or forward end of a cylindrically shaped cable bushing I5. The bore vafforded in bushing IB -m'ay have any desirable diameter so that the bushing may be fitted over and surround a cable I6 as more fully hereinafter described.

The rear end of shell Il) has a shallow, annular groove I1 in its inside surface to receive a washer I8 of brass or other suitable metal disposed with its plane parallel to the plane of flange Il of bushing I5. The circular hole afforded in washer I8 is coaxial with and considerably smaller :ln diameter than the bore in the bushing I5. A metallic substantially funnel-shaped or hollow cone-shaped member I9 is disposed so that its neck portion has a loose flt within the hole of the washer I t when a cable is not attached thus leaving an annular space between the washer I8 and funnel I9 for a portion of the outer conductor of a cable to overlie the neck portion and underlie the washer as hereinafter described. The flaring portion of funnel I9 opens forwardly into the shell Ill.

A substantially cyllndrically-shaped hollow sleeve 20 constructed of porcelain or any other suitable arc-resistant rigid insulating material is disposed coaxially within the shell I II, with its inner end 2| located substantially midway of the length of cylindrical shell I Il and its outer or forward end (to the right in Fig. l) slightly within the forward end of shell I0. The outside diameter of the sleeve 20 is somewhat less than the inside diameter of the shell III, such that an annular recess'or cavity 22 is formed between the inner wall 23 of shell I0 and the outer wall 24 of sleeve 20. The inner end portion 2| of sleeve 20 is enlarged to flt snugly and securely with the inner wall 23 of shell III or it may be flared to form a wedge-shaped space between wall 23 and the inner-end 2| of sleeve 20 to permit a binding agent 25, such as cement, to be inserted in the wedgeshaped space for securing the sleeve 20 to the shell I0. If desired, a portion of the inner wall 23 and the outer surface of the enlarged or flared portion 2| may be notched or grooved as at 20 to improve the binding action of cement 25, or alternative means employed.

The inner wall 21 of sleeve 20 defines a bore of substantially uniform diameter along the major portion of its length. The inner end of the bore may be flared as at 28 to provide a funnelshaped recess opening into the space 29 within the rear end of shell III. A portion of the forward or outer end oi' the sleeve 20 may have a slightly larger internal diameter to receive ar substantially cylindrical contact member 30 of brass -or other suitable 'conducting metal. Contact member Il 4may be provided with a ange 3| for abutting adjacent surrounding portion ofinner wall-2T of sleeve 20 may be grooved or notched to improve the binding action of the cement 33, or alternative means employed.

Contactfmember 30 has a reduced neck portion or center contact 3l extending forwardly with its end substantially in the same plane withY the forward end of sleeve V2|), thus defining an annular recess 35 between the center contact 34 and the inner wall 21 of the sleeve 20. Contact member 30 is provided with an axial bore 36 throughout its length adapted to receive the inner conductor of a cable as herein described.

Inner wall 23 of shell I9 may be provided with a ring or annular ilange 31 to abut the inner end 2| of the insulating sleeve 20 to secure sleeve 20 against inward movement. This is desirable inthe assembly of the plug element so that the sleeve 20 is held in place before and during the application of the sealing material, such as cement 25. Flange or ring 31 may be integral with the shell I6 or desirably may be in the form of a washer secured to the shell in any suitable manner. Screws 38 may be threaded through the shell and washer for a purpose hereinafterdescribed.

Upon the outer surface of shell and substantially midway of its length is mounted an annular coupling 39 preferably having at its rear end an inwardly disposed flange portion 40. Coupling 39 is held against longitudinal movement towards the forward end of shell by an annular flange 4| integral with shell or secured thereto by any desirable means as shown. The forward end of coupling 39 is internally -threaded at 42 for threaded connection to the both directions.

The socket element is illustrated in Fig. 2 and compress a cylindrical shell 50 of metal, such as steel or brass, having a slightly larger internal diameter than the outer diameter of shell I0 of the plug element to permit shell 50 to be in snug sliding engagement over` shell I0 when the plug and socket elements are being connected. The forward end (to the left in Fig. 2) of shell 50 is externally threaded at 5I to engage with the threaded portion 42 of coupling 39 of the plug element. The externally threaded portion desirably may be on an annular flange or ring 52 integral with or secured to the rear end of shell 50 in any suitable manner, such as by welding, and may be provided with a lock ring 53 in threaded engagement therewith.

The forward end of shell 50 may also be provided with an annular groove for receiving a gasket or rubber washer adapted to seat against the ange 4| of the plug element.

The rear end (to the right in Fig. 2) of shell 50 has an external annular iiange 54 integral paratus (not'show-n) to which connection is desired. Secured to the rear end of the shell' 50 is an annular retaining member 56, a portion of which is bent inwardly to form a cylindrical ring 51 substantially parallel with the shell 5||, thus defining an annular channel opening towards the forward end of shell 50, the free en portion forming ,a cylindrical ring 51.

A longitudinal insulating member generally indicated at 58 is disposed axially and with its major portion within the shell 50. Insulating member 58 has an enlarged cylindrical cupshaped portion 59, a reduced central portion 60 and a neck portion 6| extending from said central portion.y The central portion 60 is positioned substantially midway of the length of the member 58 and is of substantially circular cross section with an outside diameter somewhat less than the inner diameter of the ring 51 of retaining member 56, thus leaving an annular space between the ring 51 and the central portion 60. Portion 60 is secured to the inner surface of ring 51 by lling solder, cement or by other suitable means to make a tight connection. If desired, packing, such as asbestos, may be placed between portion 60 and ring 51 as at 60'. y

The enlarged cup-shaped portion 59 of member 58 has a shoulder 62 engaging the inner end of ring 51 to aid in locating the member 58`within shell 50 and to improve the tightness of the ,connection between member 58 and shell 50. A cavity 63 of substantially circular cross section is defined by cylindrical rear sleeve portion 6| of the cup-shaped portion 59. The walls of sleeve portion 64 have such thickness that the sleeve 64 may iit into the annular recess 22 of the plug of Fig. 1. The neck portion 6I of the insulating member 58 extends rearwardly beyond the shell 50 and may be externally grooved or ribbed along its length to provide a longer insulating surface. A metallic contact member 65 is secured to the rear end of neck portion 6|. Contact member 65 may be a disc or dish-shaped member disposed with its plane perpendicular to the axis of neck portion 6| with its wall spaced from and surrounding the end of neck portion 6|. Contact member 65 may be secured to the end of the neck portion 6| by cement, solder or aiyssother suitable securing means as indicated a The insulating member 58 is axially bored throughout its length as indicated at 66, the rear end of the bore communicating with the cavity 63 within the cup-shaped, enlarged portion 59. A metallic electrically conducting connector rod 61 is positioned within and throughout the length of the bore 66, at its rear end being electrically in contact with the contact member 65 and at its forward end having a substantially cylindrical sleeve portion 68 extending into the cavity 63 a short distance. The cylindrical sleeve 68 is of such dimension that it is adapted to t snugly over neck portion 34 of contact member 30 of the provided with a longitudinal slot or slots to imwith or suitably mounted on the outer surface of shell 50 and having a plurality of spaced-holes 55 for receiving bolts or screws to permit secure mounting of the socket element onto approve resiliency and to facilitate the sliding of the sleeve 68 over the contact 30. The rear end of the rod 61 terminates in a lug or stud 69 projecting through the center of contact member 65,

and secured thereto for connection with a transmission wire or for contact with brushes of a u rotating spark gap assembly, or any other electrical contact element of apparatus to which the socket element may be attached. If desired, the stud l! may be center-tapped or provided with a threaded recess 1l.

In the structure described the several cylindrical members of the plug element and socket element are concentric relative to the longitudinal axes of the plug and socket elements. It will be noted that, when the plug element and socket element are connected, the respective axes will be co-linear, the cylindrical members of both elements thereby being concentric to the common axis. In this position the cup-shaped member Il of the socket element will surround the cylindrical insulating member 2II of the plug element and it is preferably spaced therefrom to provide an air-gap, thus improving the insulating properties of the connection.

The plug and socket of the present invention as described above is particularly adapted for use with a coaxial type cable capable of conducting high voltages. Such a cable I6 as shown in Figs. l and 3 has usually, in sequence, a central conductor 1I, a layer of insulating material 12, such as rubber or the like, a layer of copper braid sheathing 13 constituting an outer conductor of the cable, a layer of insulating cotton tape 14, a sheath or shield of steel braid armor 'I5 and an outer sheath 16 of natural or artificial rubber ("neoprene) or other suitable insulating material. It will be understood that Fig. 3 is an expanded view of a cable end to more clearly illustrate the construction thereof and the manner in which the indicated members of the plug element are applied to the cable end in the assembly but that this view should not be taken in the light 4of the following description as showing the exact dimensions or the relative lengths of each layer or of the exact positioning of the plug elements thereon. Also, it will be understood that while the description is directed to a cable of the above kind, the present invention may be used with any cable of similar construction having an inner conductor and an outer conductor or shield spaced therefrom by insulating material.

In attaching the plug element to a cable end, of the kind referred to, the clamping nut I2 and the cable bushing I5 are slipped over the end of the cable I6 for any desired distance. The outer sheath of insulating material 16 is removed for a short distance, for instance 2%" from the cable end. The layer of steel braid shielding is then removed from the cable end to say within 1%" from the end of the outer sheath 'IB and the remaining portion is unwoven to the end of the outer sheath and the unwoven strands bent outwardly at right angles as indicated at 11 in Fig. 1. The cable bushing I5 is then moved into position against the bent strands which are trimmed off so that the protruding ends are slightly below the outer edge of the flange I4 of the bushing. If there is a layer of cotton tape, this is removed down to a point where the steel braid strands are bent. The metal washer I8 may then be moved over the copper braid 13 and down to :a point where the outer sheath terminates, thereby positioning the outwardly protruding bent portions 11 of the steel strands between the washer I8 and the flange I4. If desired the surfaces of the washer IB and the flange I4 engaging the bent strands may be serrated or notched to bite into the strands, when the plug is fully assembled, and provide a better frictional clamping action on the strands. The layer of copper braid 13 then is removed to within about 1/8" from the washer Il and the funnel Il slid over the inner layer of insulating material 12 so that its neck' portion enters the hole of the washer- Il whereby its neck portion slides under the layer of copper braid spreading it outwardly over the neck portion and for a short distance over the flared portion of the funnel Il, as indicated at 1l in Fig. 1. The copper braid 13 Is secured to the funnel member I! and to the washer It by solder. The inner layer of insulating material 1! should be removed for a short distance from the end of the inner conductor 1I to expose the end portion of the inner conductor and, if desired, the insulating layer 12 may be tapered toward the end of the inner conductor. 'I'he cable end is then ready to be inserted into the rear end of the plug element Il. This may be done by inserting the exposed end of the cable into the cavity 29 so that the exposed end of the inner conductor 1I will fit into the bore 3i of the contact member SII. Upon engaging and tightening clamping nut I2 on the threaded portion II of shell I0, the cable end is forced tightly into position. If desired, washer I8 may be soldered or otherwise secured into the open rear end of shell I0. The tightening of the clamping nut I2 insures that the flange Il of bushing I5 is clamped tightly against the outwardly bent strands 11 of the shieldingv to thus prevent the cable from turning or moving longitudinally with respect to the assembled plug element. Any excess of length of the center conductor which may protrude beyond the bore Il of contact member 30 should be cut off and solder may be flowed into the bore to make a more secure connection. If desired, the center conductor and the end of the neck portion $4 may be filed or otherwise smoothed so that the end will be left rounded, thus permitting easier engagement with the socket sleeve 68.

With the plug element and cable end thus assembled, it will be noted that the plug element is substantially fluid tight. It may be found desirable, to insure better insulating qualities. to fill the inside of the shell I0 with a dielectric material which will also serve to eliminate any air space within the plug element. This may be accomplished by providing'a closable aperture in the wall of the shell I0 through which dielectric material, such as wax, may be inserted. Preferably, however, one of the screws 38 in the annular ring 31 may be removed thus leaving an aperture for insertion of dielectric material after which the screw is replaced. Any suitable dielectric material, such as that sold under the trade names Dow-Corning Ignition Sealing Compound #4 or Anaconda Superseal #150, may be used depending upon the specific use to which the connector of the present invention is to be applied.

It will also be appreciated that the connector of the present invention is capable of being easily detachable. This may be accomplished by simply unscrewing coupling 39 of the plug element lfrom threaded engagement with the threaded portion 5I of the socket element and then pulling the plug element away from the socket element. Similarly the plug and socket element may be easily and quickly connected by the reverse procedure.

Upon connecting the plug element with the socket element, it will be obvious from the above description that the outer shell 5U of the socket element, because of its slightly larger diameter, is

adapted to overlap forward end of shell I0 of the plug element and to be secured thereto. As described herein the enlarged cup-shaped portion 7. of the .insulating'memb'er 58 is of such dimension that it may be received inthe annular recess between the outer shell I vand the inner insulating member 20 of the plug element; and the socket sleeve-r 68 will'override and be in good electrical contact with the neck portion 34 of contact member 30. It will be appreciated that in the assembled position of the plug andr socket'element, thereis a continuous, good electrical connection between the inner conductor of the cable through the neck portion 34 of contact 30y with the socket s leeve portion 68 of the socket element through the metal tube 6T within the insulating member 58 to the contact member 65. Any current that may flow in the outer conductor of the cable is passed through the washer I8 tothe outer shell I0 of the plug element and by the continuous metallic contact between the outer shell I0 of the plug element and the outer sleeve 50 of the socket element is passed to the flange 54 and thence to the apparatus to which the socket element may be attached, or vice versa. .It will be understood, however, 4that the high voltages carried by the cable are usually passed through the inner conductor only, the outer conductor being used as a shield to preagsesgaae I opposite end of said contact member havinga're vent high voltage currents from' passing out of the cable. It will be obvious that in passing high voltage pulses through the connector of the present invention, possibility of losses or dashing-over from the inner conductor to the outer conductor or to any surrounding medium is greatly reduced due to the telescoping relation of the insulating members, the space therebetween, and the increased distance between the inner and outer conductors.

A preferred form of the socket element has been described above for us`e as a terminal connection. It will be appreciated that a similar form of socket may be used for connection to a cable end so that the plug and socket elements may provide a detachable connector between two lengths of cable. This may be accomplished by providing suitable modifications of the socket element as will be readily understood by those skilled in the art in the light of the foregoing description.

What is claimed is:

1. A detachable connection for high voltage -transmission coaxial type cable having in combination a plug element and a socket element separably engaged therewith, said plug element comprising an outer cylindrical metallic shell, one end of said shell being in threaded engagement with an annular clamping nut, a cylindrical cable receivingvbushing held by said nut, `a metallic washer on the shell positioned to surround a portion of the cable end and clamp outwardly bent portions of the cable sheathing between said bushing and said washer, a funnel-shaped member arranged to receive an inner insulator portion of the cable end and to engage within an end portion of an outer conductor of said cable in said washer vwhereby tightening of said clamping nut on said vshell iirmly secures said cable end to said shell and electrically connects the outer conductor to said outer shell, a substantially cylindrical sleeve of rigid insulating material fixed and spaced coaxially within the non-threaded end of said shell to provide an annular recess, and a metallic contact member rigidly mounted Within and near the free end of said major portion of said sleeve, said contact member having a vbore therethrough, one end of said bore communicating with the cavity defined by the inner Walls of said shell and said insulating sleeve and connected with an exposed -end-of the center conductor of said cable, the

duced projecting neck portion.

2. A detachable connection as claimed in claim 1 wherein said socket element comprises a hollow cylindrical metallic sleeve having slidable fit with the outer shell of the plug element, the rear end of said metallic sleeve carrying an inwardly disposed retaining ange having a p ortion bent toward the opposite end of said metallic sleeve to deilne a cylindrical ring substantially concentric with said sleeve, a coaxial substantially cylindrical insulating member iixed in said ring having a hollow cup-shaped portion within and spaced from said sleeve and opening toward the forward end of said sleeve, said cup-shaped portion projecting into the recess between said outer shell and said insulating sleeve of said plug element, said insulating member having a neck portion extending rearward beyond the rear end of said sleeve andA provided with an axial bore, a metallic contact member mounted on the extremity of said neck portion, a metallic electrical conductor disposed within said bore, therear end of said conductor connected with said contact member, the forward end of said conductor extending into the recess within said cup-shaped portion and having a tubular shape and electrically engaged with the reduced neck portion of the contact member of said plug element and separable coupling means externally mounted on said sleeve and the shell of said plug element coupling said plug element to said socket element.

3. A socket element for a detachable connector for high voltage transmission coaxial type cable, comprising a hollow cylindrical metallic sleeve, an inwardly disposed retaining flange having a portion bent toward the forward end of said metallic sleeve to deiine a cylindrical ring substantially concentric with said metallic sleeve, a coaxial substantially cylindrical insulating member having a hollow cup-shaped portion within and spaced from said metallic sleeve and opening to'- ward the forward end of said metallic sleeve, said insulating member having a central portion in substantially uid-tight connection with said ring and a neck portion extending beyond said central portion and beyond the rear end of said metallic sleeve and provided with an axial bore, a metallic contact member mounted on the end of said neck portion, a metallic electrical conductor disposed within said bore, the rear end portion of said conductor connecting with said contact member, the forward end of said contact extending into the recess within said cup-shaped portion and having a tubular shape.

4. A connector member for terminating a coaxial cable, of the type which includes an inner conductor, a tubular dielectric encircling said inner conductor, a tubular outer conductor encircling said dielectric anda tubular sheath encircling said outer conductor, which connector member comprises a tubular shell of conducting material, a washer of conducting material abutwasher so as to grip said end of said tubular sheath between said flanged portion and said washer, a tubular substantially funnel-shaped member provided with a rearwardly directed tubular neck extending through the said washer and spaced therefrom andreceiving therearound the end of said outer conductor of said coaxial cable within said washer, larigid dielectric sleeve secured to the interior of said metallic shell, and a contact member secured to the interior of said sleeve and provided withia bore having the end of said inner conductor ofJ the said coaxial cable engaged therein, al1 of the elements of said coaxial cable and of said connector member being substantially coaxial.

ROBERT R. STEINKE.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Numbei` Name Date 1,497,002 Sanderson June 10, 1924 1,896,444 Fossati Feb. 7, 1933 1,991,230 Shanklin Feb. 12, 1935 2,173,643 Moser Sept. 19, 1939 2,174,377 Bowden et al Sept. 26, 1939 2,294,738 Bruno Sept. 1, 1942 

